Golf club



N. S. MAIN GOLF CLUB March 14, 1933.

Filed Dec. 2", 1928 FIG. I.

Patented Mar. 14, 1933 UNITED STATES NORMAN s'rnwnm' MAIN, ornmmrneowsoornnnn GOLF CLUB,

Application filed December 2c, 1928, Serial No. meant-a Great BritainDecember 30,1927.

This invention relates to the heads of golf clubs. I have found thatif'a ball is centre of the club face and swerves while travellingthroughthe air, while a ball hit off the heel of the club head-diverges to theother side, and that this efiect is due to the twisting of the club headon impact.

In my invention I minimize or eliminate this divergence by thecombination of two features of construction eachof which by itself hasbeen previously adopted in a golf club, viz

(l) by constructing the club head of a light material and forming itwith a heavier heel and toe with the object of giving it the maximummoment of inertia about its vertical axis of rotation under impact, thatis, about a vertical axis which passes through or close to the centre ofgravity of the club head, and (2) by making the striking face slightlycylindrical, the curvature being approximately a small segment of alarge cylinder 5 with a vertical axis.

produced by the separation of the added,

The heel and toe of the club head may be loaded by the known method ofinserting weights away from the central portion of the striking face. Asmuch effect as possible is weights and the curvature of the face is keptas slight as possible. On account of the weight of the shaft of the clubthe loading at the toe is made greater than at the heel.

My invention is applicable to either putters or drivers or other similarclubs. In the case of a driver, the heel and toe may be made heavier bythe known method of inserting a plug of lighter material in the centralportion of the club head, for example, by boring a recess in the centralportion of the club head and filling said recess with a lightermaterial. 7

The accompanying drawing illustrates two examples of golf club headsconstructed according to my invention.

Fig. 1 is a plan view and Fig. 2 a face view of a putter. Fig. 3 is aplan view of a driver.

Referring to Figs. 1 and 2, it will be seen part of the face.

that the" club headhas its striking face A large diameter; The heel andtoe of the club headare loaded by weights B inserted in recessesextending upwards from the sole of the club, the recesses being closedby metal plates C secured'to-the sole of the club head which is recessedso that the metal plates C are flush on the surface with the sole ,ofthe club head. 1

In the driver shown in Fig. 3, the striking face is a convex surface Awhich-forms part of the surface of a vertical cylinder of large diameterand the club head is loaded at the heel and toe by weights B inserted inV recesses closed by metal sole plates C' similar to those described-with reference to Figs.

l and 2.

The curvature required varies with the shape and weight of the'club headand may be found'by mounting-astraight faced club loaded-as abovespecified on an axis which is fixed at right angles to the grip and inthe same plane as the club face. The club is rotated on the said axis bymechanical means and the extent of the diver 'ence of the flight of aball struck successively with different parts of the face is noted. Fromthis, the curvature necessary to correct the divergence may beapproximately calculated and 'aclub with this curvature can then be c Itested and corrections made on the curvature until the best curveisfound to procure an approximately straight shot from any In the caseof a club which does not raise the ball from the ground, the curvaturerequired is a concave one, in the case of a club whichelevates the ballinto the air, the desired curvatureis found to be a convex one. o

The curvature required to give perfect correction is not trulycylindrical, but apparticularly at the heel.

I claim. i

proximates more towards a parabolic curve,

1. A golf club head comprising a heavier heel and toe portion thancentral portion to;

increase'the moment of inertia'of the club' head aboutits vertical axisof rotation under PA ENT" opnc v struck. from said face.

8. A golf club head comprising a heavier heel and toe portion thancentral portion to p 7 increase the mom'entof inertia of the'club I headabout its vertical axis of rotation under 7 impact, in combination witha striking' face curved about a vertical axis;,the,curvature being suchas to"impar't an approximately straight motion to a ball struck from anypart of the fa-ce.

4.115; golf club head comprising a heavier heel and toe portion thancentral portion to increase the moment of inertia of the club headabouta verticalaxis' passing approxi mately through the centre ofgravity of. the club head, in combination With a striking face Whosesurface, forms part of a vertical cylinder of large diameter. l

5. A golf club head as, claimed in claim 4 having a concave strikingface I A golf club head comprising a heeland v V toe portion loaded toobtain the maximum momentof inertia of the club head about a verticalaxis passing approximately through the centre of gravity of the clubhead, in

combination With a striking face Whose surface forms part of a verticalcylinder of large diameter. I .v

The foregoing specification signed at Glasgow this 11th day of December,1928.; v NORMAN STEWVART MAIN.

